Another draught presents us with the Fifteen-spined Stickleback,[61] a
little fish, remarkable for its form, but much more so for its habits.
It is ordinarily about five or six inches in length, very slender and
lithe, from which circumstance, combined with a protrusion of the
jaws, which gives it a sinister expression, it is on some parts of
the coast called the Sea-Adder. The lower jaw projects considerably
beyond the upper, which indicates that the fish habitually takes its
food from a point above the level of its own body. The dorsal and
anal fins are high and short, so as to form, when erected, nearly
equal-sided triangles; but the former is preceded by fifteen minute
sharp erectile spines, each of which has its own little membrane, and
all together represent the spinous portion of the dorsal fin in such
fishes as have but one, as the Blennies, or the first dorsal in such
as have two, as the Weevers. The caudal is narrowly lozenge-formed, as
ordinarily carried, but becomes fan-like when expanded. The colours are
deep sepia, or olive-brown, cast into streaks and irregular clouds, on
the sides, where they are interrupted by white, and by a rich golden
yellow, that extends over the inferior surface: the dorsal and anal
fins are white, each crossed by a broad conspicuous band of brown; the
eyes have golden irides.
We frequently see this attractive little fish hovering about the long
tufts of wrack and tangle that hang from perpendicular rocks, and
from the quays and wharves of our harbours. It diligently hunts about
for its minute crustacean prey, in picking off which it assumes all
varieties of position “between the horizontal and perpendicular, with
the head downward or upward,” thrusting its projecting snout into the
tufted weed, and snatching its morsel with a sudden jerk.
It is, however, in its domestic relations that this little fish
presents itself in the most interesting aspect. It was known ages ago
to Aristotle, that some fishes are in the habit of forming nests, in
which they deposit their eggs, and bring up their young with a parental
care not inferior to that of birds. Until lately, however, this fact
was supposed to be fabulous; and fishes were believed by the greatest
masters of modern zoology to be utterly destitute of the parental
instinct. Recent research has in this, as in so many instances, proved
the exactitude of the old Stagyrite’s knowledge, and we now know that
several fishes of different families nidificate. The Sticklebacks, most
of which inhabit in common our marine and fresh waters, are remarkable
for the manifestation of this faculty, as was first shown by Mr.
Crookenden, of Lewisham, in 1834, and as has since been proved, with
many interesting details, by Mr. A. Hancock and Mr. Warington. Our
Sea-Adder, which is exclusively marine, was first ascertained to be a
nest-builder by the late Dr. George Johnston, who mentioned the fact in
the “Transactions of the Berwickshire Naturalists’ Club” in 1839. But
the most interesting account is that of Mr. R. Q. Couch, who noticed
the facts on the coast of Cornwall, and thus records them in a paper
read before the Royal Institution of that county:--